ETHER_ATON(3) Linux Programmer s Manual ETHER_ATON(3)

NAME ether_aton, ether_ntoa, ether_ntohost, ether_hostton, ether_line, ether_ntoa_r, ether_aton_r - Ethernet address manipulation routines

SYNOPSIS #include <netinet/ether.h>

char *ether_ntoa(const struct ether_addr *addr);

struct ether_addr *ether_aton(const char *asc);

int ether_ntohost(char *hostname, const struct ether_addr *addr);

int ether_hostton(const char *hostname, struct ether_addr *addr);

int ether_line(const char *line, struct ether_addr *addr, char *hostname);

/* GNU extensions */ char *ether_ntoa_r(const struct ether_addr *addr, char *buf);

struct ether_addr *ether_aton_r(const char *asc, struct ether_addr *addr);

DESCRIPTION ether_aton() converts the 48-bit Ethernet host address asc from the standard hex-digits-and-colons notation into binary data in network byte order and returns a pointer to it in a statically allocated buffer, which subsequent calls will overwrite. ether_aton() returns NULL if the address is invalid.

The ether_ntoa() function converts the Ethernet host address addr given in network byte order to a string in standard hex-digits-and-colons notation, omitting leading zeros. The string is returned in a stati- cally allocated buffer, which subsequent calls will overwrite.

The ether_ntohost() function maps an Ethernet address to the corre- sponding hostname in /etc/ethers and returns non-zero if it cannot be found.

The ether_hostton() function maps a hostname to the corresponding Eth- ernet address in /etc/ethers and returns non-zero if it cannot be found.

The ether_line() function parses a line in /etc/ethers format (ethernet address followed by whitespace followed by hostname; ’#’ introduces a comment) and returns an address and hostname pair, or non-zero if it cannot be parsed. The buffer pointed to by hostname must be suffi- ciently long, for example, have the same length as line.

The functions ether_ntoa_r() and ether_aton_r() are reentrant thread- safe versions of ether_ntoa() and ether_aton() respectively, and do not use static buffers.

The structure ether_addr is defined in <net/ethernet.h> as:

struct ether_addr { uint8_t ether_addr_octet[6]; }


BUGS The glibc 2.2.5 implementation of ether_line() is broken.

SEE ALSO ethers(5)

COLOPHON This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at

GNU 2002-07-20 ETHER_ATON(3)